[TowerTalk] Guying a self-supporter

[Roger (K8RI)]

Hmmm This was supposed to go to the group, but apparently I hit the 
wrong key...again.


K7LXC at aol.com wrote:
>  
> In a message dated 11/3/2008 12:45:53 P.M. Pacific Standard Time,  
> towertalk-request at contesting.com writes:
>
>  
>>  This subject has been debated before.  Your analysis of  
>> self-supporting
>>     
> towers and guying is another example of  misinformation!  Let me suggest
> you obtain the facts next time you  post or other wise state that it is
> your opinion.  The company that  manufactures the self-supporting towers
> I use, RECOMMENDS guying ...  fact!
>  
>   
Angles are the angle between the tower and guy line.
You can get the same answers by using the Sin of the angle between the 
guy and ground.
Top guys on 100' 45G 3 @ 660# tension. Cos(30)*660 = 571*3 = 1715 rounded
Middle guys 3 @ 440# Tension Cos(45)*440=311*3= 933
Bottom guys 3 @ 440# Tension Cos(60)*440=229*3=660

Tower sections 70# X 10 = 700.
Base section 35#
Antennas and mast 300#
Rotator  45#
Coax and control cables  100#
Guy bracket assembly 23# X 3 = 69#
Total = 1249 Give or take a 100.
Were I to use EHS guys instead of Phillystran I could easily add another 
300 to 600# while the Phillystran weights well less than 100# per 1000 
feet.

That means they guys on my tower exert an additional 3300# on the base.  
That is well more than double the total tower and antenna system 
weight.   Free standing, or Self Supporting towers are build 
considerably stronger than guyed towers as they have to serve the 
function of those guy wires internally. Some are designed to allow 
guying as well.  The question them becomes, If permitted how does guying 
the self supporting tower affect the wind load and weight support 
ratings.  Guying a tower with properly tensioned guys can easily add 
more than twice the load to the base.  So a 1500# tower could end up 
with 4500# on the base structure.

IF the tower manufacturer says their self supporting tower may be guyed, 
stick strictly to their recommendations as to guy strength, tension, 
wind load, and antenna weight.

I'm surprised a reputable manufacturer would recommend guying a self 
supporting tower.

Roger (K8RI)
>     Okay, I'll bite. Who is the manufacturer -  Trylon? Delhi? How 
> about a reference? I've never seen a US tower manufacturer  say to guy 
> a self-supporting tower so maybe it's a Canadian thing. And I have  
> seen guyed Delhi towers. (Delhi towers are exact copies of the Rohn BX 
> line  that includes straight sections so you can wind up with a beefy  
> self-supporting/guyed tower.)
>  
> Cheers,
> Steve     K7LXC
> TOWER TECH
>
>
>